The earliest version of the IEEE 802.11 standard provided a data rate of 1 Mbps. In a subsequent amendment, namely IEEE 802.11b, a physical layer data rate of 11 Mbps was provided. With the introduction of orthogonal frequency division multiplexing (OFDM) in the IEEE 802.11g and IEEE 802.11a amendments for 2.4 GHz and 5 GHz bands respectively, the data rates supported were increased to 54 Mbps at the physical (PHY) layer. The IEEE 802.11n amendment increased the data rates supported to 100 Mbps on top of the MAC layer.
Wireless Local Area Networks (WLANs) with very high throughput (VHT) of greater than 100 Mbps on top of the MAC layer are being designed. VHT WLANs may also include features such as multi-user multiple-input multiple-output (MU-MIMO) techniques, coding features, power save features, and the like. MU-MIMO technology enables simultaneous transmission to multiple WTRUs on the same frequency, and also simultaneous reception from multiple WTRUs on the same frequency. VHT protection features for VHT packet transmission and legacy packet transmission will also be needed. In a scenario with densely deployed VHT APs, overlapping basic service set (OBSS) management is necessary because of high interference from neighboring BSSes. In a television white space (TVWS) scenario, independently operated networks/devices, (and even dissimilar networks/devices in radio technology), are expected to coexist and operate in the same common TVWS frequency spectrum. These are just a sample of the features and capabilities needed in VHT WLANs.